IcECLAMATION OF ARID LANDS NEWELL. 177 



AMOUNT OF WATER USED. 



The phrase " duty of water " is used frequently indicating the 

 amount of water required during the year or crop season for success- 

 ful irrigation. The duty of water is usually expressed in depth 

 over the surface, for example, the statement that the duty of water 

 is 3 acre-feet means that during the crop season an amount of water 

 has been applied sufficient to cover an acre to a depth of 3 feet. As 

 the acre consists of 43,560 square feet, a duty of water of 3 acre-feet 

 corresponds to the use of 130,680 cubic feet j)er acre during the year, 

 or nearly a million gallons (977,550 gallons). 



The use of water is also frequently expressed by a statement that 



1 second-foot will irrigate 100 acres, more or less. This means that a 

 stream 1 foot wide and 1 foot deep flowing at the ra^-'^ of 1 foot per 

 second, or in other words, 1 cubic foot of water per second flowing 

 throughout the irrigating season will water 100 acres. By a simple 

 arithmetical computation, it will be found that 1 cubic foot per 

 second flowing for 24 hours will cover an acre to a depth of very nearly 



2 feet (1.98 feet). In other words 1 second-foot is nearly equivalent 

 to 2 acre-feet per day; thus, if the irrigating season is 90 days in 

 length, 1 cubic foot per second for 90 days will amount to a delivery 

 of nearly 180 acre-feet, or cover 100 acres to a depth of 1.8 feet. 



NECESSITY OF GOOD MANAGEMENT. 



The value of the crop produced and the consequent ability of the 

 farmers to return the cost of the investment are dependent directly 

 upon water being received on each farm in proper quantity and at 

 the righl; time. If too much water is applied the crops will be corre- 

 spondingly injured, the available soluble salts in the soil will be 

 washed out or brought to the surface, the land depreciate in value, 

 and large areas will be destroyed. With intensive cultivation and 

 the crop production in the more valuable fruits, berries, or vegetables 

 under ideal conditions, the yield may be several hundred dollars an 

 acre. By a slight error in handling the water the crop value may be 

 lessened by a hundred dollars an acre or more. 



Although the net product per acre may appear to be large and sat- 

 isfactory, and it is impossible to prove that higher values might 

 have been reached, yet the man who thoroughly understands the 

 situation appreciates that there has been a loss of $100 per acre, 

 which is directly attributable to lack of good management, and that 

 under better conditions higher values woidd have been attained by 

 the farmers. This possible reduction of crop values in a highly 

 developed agricultural area of say 10,000 acres at $100 per acre 



9757S°— SM 1910 12 



